Centrifugal pump



Dec. 16, 1952 H. E. LA BOUR 2,621,600

I CENTRIFUGAL PUMP Filed Sept. 10, 1948 3 SheeQS-SheQt l A 3+ 5'. 40 5' 3 54 6 P49 Q J IN VEN TOR.

ffczrzzg E1 LaBouw Dec. 16, 1952 BOUR 2,621,600

CENTRIFUGAL PUMP Filed Sept. 10, 1948 5 Sheets-Sheet 2 Patented Dec. 16, 1952 UNITED STATES PATENT OFFICE CENTRIFUGAL PUMP Harry E. La Bour, Elkhart, Ind. "Application September 10, 1948, Serial No. 48,586

"My invention relates to centrifugal pumps which are intended to operate with a positive head of liquid on the intake. Such pumps are sometimes referred to as submerged or drowned although they are not actually submerged or drowned in the liquid but have their intake connected to a source which through a gravity head or an artificial head delivers liquid into the intake of the pump under some degree of pressure. p

Under such conditions, the shaft seal of the pump must be tight at all times, i. e., whether running or standing still. Leakage at the seal is always, highly objectionable, and in some cases not permissible, for'example, when the liquid to be pumped is corrosive or volatile, or produces a health or fire hazard, or, even where the liquid is particularly valuable.

Shaft seals of the packed type which require that a more or less yielding packing material be held in fluid tight engagement with the shaft are widely used, but leave much to be desire They require constant attention because the ru bing contact produces heating and wear. Even slight eccentricity of the shaft makes it almost impossible to keep the joint tight and tends to require excessive tightening of the packing upon the shaft which accelerates heating and wear. There have been numerous attempts to dispense with the conventional packing and to employ a gap between the shaft and the pump case which gap it is then proposed shall be sealed with liquid in such manner that air will not be drawn in and liquid will not escape while the pump is running. Then it is proposed when the pump stops to close the gap by applying a sealing ring or plug to the gap under the automatic control of a centrifugal governor to provide a contacting or. static seal. Attempts to develop such pumps are exhibited in numerous patents. See particularly U. S. Patent No. 1,346,926 and French PatentNo. 582,365. Although the demand for a packingless centrifugal pump has been persistent and widespread, no satisfactory solution of the problem has heretofore been brought onto the market.

My investigation and analysis have led me to conclude that there are several basic difficulties which are required to be overcome. First, the organization of the pump with the two seals must be such as to insure the ability of the pump and the seals to operate satisfactorily under the conditions for which the unit is designed to operate. The kinetic seal must always have a charge of liquid which is neither too much um Claims. (Cl. 103103) too little, and the static or positive seal must be applied at the right time, neither too soon nor too late, and must be tight when applied. Thisthe prior art has failed to accomplish.

Second, the seals and the pump must be so organized and combined into the unit as to be capable of convenient construction and servicing, and of giving long and uninterrupted. service. This the prior art has failed, to accomplish.

Third, the control of the application and release of the positive seal to the gap must'be so coordinated with the functioning of the pump and the hydraulic or kinetic seal that on the one hand there will be no instant during which the seals'both failto prevent leakage of liquid from the pump, and on-the other hand, excessive wear of the positive seal will not be incurred.

The prior art has failed to meet this requirement, with the result that positive discharge of liquid at the gap is unavoidable. Where the liquid to be pumped is highly corrosive or caustic, such, for example, as a strong acid or alkali, such ejection of liquid even in small amounts is highly objectionable, not only because of the possibility of damage to property, but also'because of danger of injury to personnel.

Fourth, the organization of the pump and the two seals must be such that the integrity of the mechanical drive is invariably maintained. In prior attempts to construct such a pump unit it has been impossible to exclude leakage of the medium being pumped from the shaft bearings with resultant destruction of the same, particularly in case of corrosive liquid or liquid with entrained solids. The prior art has failed to meet this requirement.

Fifth, the organization should be capable of maintaining the kinetic seal without requiring supplemental liquid to be supplied from the discharge or from an outside source. In many cases no diluting liquid for the kinetic seal is permissible. In all cases the admission of liquid for maintaining the seal should be inherently automatic. Prior schemes for supplying liquid for the seal require the attention and judgment of an engineer. The art has failed to meet the requirement.

There may be other reasons for the failure of prior units to meet the demand, but no unit will, in my judgment, meet the users demands without meeting at least the above requirements.

The objective of the present invention is to provide a centrifugal pump and seal unit suitable foruse with an intake head and wherein the sealing of the shaft is attained by the joint and combined action of a kinetic liquid seal and a positive contact seal so organized in structure and method of operation as to meet the above and other requirements. In brief, my aim in the present invention is to meet the commercial demand for a satisfactory packingless centrifugal pump for submerged service.

The preferred embodiment of my invention which is hereinafter illustrated and described in detail is organized around certain novel and basic concepts. The first concept is to organize the pumping parts and the two seals around a central tubular sleeve, with the kinetic seal arranged at one end, and the static or contact seal at the other end, with the active pumping parts disposed about the central part of the sleeve between the two sealing units, and driven by a shaft extending down through this sleeve.

Another concept is to dispose this sleeve in a vertical position with the kinetic seal below and the static seal above the pump parts proper.

By the foregoing, certain advantages are attainable. The kinetic seal is now assured of an adequate charge of sealing liquid at all times. The sleeve acts as a trap or standpipe and allows for certain fluctuations in the head of liquid on the atmospheric side of the static seal without permitting liquid to escape. The static seal is disposed with its diaphragm at the top of the sleeve where liquid, if any should escape, can be trapped and led off sidewise before it can reach the bearings. A liquid slinger can kee any film of liquid from mounting the shaft.

A further and highly significant concept is to allow the static or contact seal to be controlled primarily by the head of liquid in the said sleeve. This control may be supplemented by a spring or weight and a magnet, the activity of which is concurrent with that of the driving motor of the unit. The spring and magnet incline, but do not necessarily compel the action of the seal applying diaphragm, because the hydraulic and pneumatic forces acting upon the diaphragm are substantially greater than the force of the spring and magnet, respectively. They take control only when the larger forces are absent or diminished.

The significance of this concept resides in the ability to secure an overlapping of the effect of the two seals when that is in order, with a nicety of response of the static seal contact element to its requirements never before attained. Thus if the motor is shut down, the contact seal may be brought into contact, but no substantial pressure is brought upon the rubbing parts until thehead of liquid in the sleeve indicates that the kinetic seal is no longer efiective. imilarly, when the pump is started into operation, the contact seal is relieved of hydraulic pressure just as fast as the kinetic seal takes effect, and then the thrust of the magnet is allowed to give the contact seal its final push away from engagement with the seat or shoulder on the rotating shaft.

A further object of the invention is to organize the pump into parts which will adequately perform the essential functions and at the same time be capable of being manufactured, assembled and serviced with as little difiiculty as possible. The preferred form of pump herein illustrated involves numerous inventive concepts required for practical physical embodiment of the basic func tional concepts.

For example, the problems of disposing the main pump parts, i. e., the impeller and its casing and the inlet and discharge connections be- 4 tween the two seals at the opposite ends of the sleeve and of providing the drive for the rotating parts, have called forth subsidiary inventive concepts of unusual complexity, as will be apparent from the detailed description below.

Other advantages which flow from the above named and other subsidiary concepts will be apparent from the following specific description of the preferred embodiment.

Now in order to acquaint those skilled in the art to construct and operate my invention, I shall describe a specific embodiment thereof.

In the drawings:

Figure l is a side elevation of the pump unit of my invention, the driving motor being shown as broken away at the top;

Figure 2 is a vertical longitudinal section through the connection of the motor shaft with the intermediate shaft section;

Figure 3 is a similar vertical longitudinal section through the lower end of the intermediate shaft section, the static seal, the pump parts and the kinetic seal.

Figure 4 is a partial vertical longitudinal section and partial side elevation of the pump parts showing the construction of the volute or casing and the locaiton of the parts sectioned in Figure 3; and

Figure 5 is a diagram of electrical connections for showing the connection of the magnet to the motor circuit.

The specific embodiment herein disclosed is an acid pump, i. e., a pump having its parts which are exposed to contact with the liquid to be pumped made of a material resistant to corrosion, for example, an alloy of the type disclosed in my Patent No. 2,103,855. Obviously, the pump parts may be made of any material suitable to the intended service. This requirement is known to those skilled in the art.

The pumping unit herein illustrated in Figure 1 comprises the base I, upon which the parts are mounted vertically with the pumping unit 2 above the base. Upon the pumping unit 2 is mounted a bracket frame 3 within which are disposed the static seal members to be later described. Upon the bracket frame 3 there is mounted the motor and bearing frame 4 containing a bearing barrel in which are supported the bearings for the main shaft and its connected rotating parts, and upon which frame 4 is mounted the vertical motor 5 which is of any conventional or preferred form. The electric motor as illustrated in Figure 5 is adapted to be connected to the electric supply mains 6 by a control switch The motor leads 8 have a parallel connection 9 to a solenoid magnet lil which has a plunger ll adapted to operate a lever I2. The pump body 2 has a flanged inlet connection i4 leading to the top of the pump body and it has a flanged discharge connection If: communicating with a volute I6.

Referring now more particularly to Figure 3, the central feature of the construction involves a sleeve ll, the lower end of which carries an integral sealing disc 58 embraced by a sealing drum l9 carried on the lower end of the shaft 20. The sleeve IT has intermediate its length an external shoulder 22 above which there is a cylindrical portion 23 which fits in a central bore in the head 24 defining the top of the intake chamber 25. The bore in the head 24 has a short keyway 26, and the sleeve I1 carries a Woodruif key 21. The registration of the key 2'! in the keyway 26 may be visually observed through the intake connection I4 when the parts are to be assembled aser-coo 9 or serviced. The upper end of the sleeve I1 is threaded, as at 28, to receive the threaded hub 29 of the diaphragm cup 39. A gasket 32' covered with a suitable lubricant is interposed between the hub 29 and a shoulder in a recess or counterbore formed in the head member 24. The diaphragm cup 30 has a flange 32 with radially projecting extensions 33 which may be engaged by a spanner wrench. A heavy flexible diaphragm preferably of non-metallic material, is clamped to the flange 32 by means of the flange 35 f the drip trap 36, which has a suitable outlet connection 31 for the attachment of a hose for leading away any drip which might lodge in the said drip cup 36. Bolts 38 clamp the flanges 35 and 32 together upon the outer marginof the diaphragm 34. The drip cup 36 has an inwardly extending flange 39 which overlies closely the major part of the free area of the diaphragm 34 to restrain the deflection of the diaphragm and thereby guard against accidental rupture.

The diaphragm 34 is apertured at its center and a mounting is riveted to a backing plate 43-upon the opposite side of the diaphragm. The mounting ring 40 has cemented in an annular recess the anti-friction ring 42 which may, for example, be made of graphite or other suitable material resistant to corrosion and Wear. A pair' of arms 44 are formed on the mounting ring 49. These arms 44 extend above the rim of the drip cup 36 and have pivoted openings or recesses arranged in diametric relation with respect to the axis of the shaft for the insertion of pivot pins 45 which pins are secured in and are removable from the two branches of arms 46 of the lever I2. The lever I2 is a second class lever pivoted at its fulcrum 4! on a stationary frame part, in this case the bearing clamp ring 48 bolted to the bearing support plate 49. The plate 49 has integral therewith a bearing barrel 59 (see Figs. 2 and 3). The movable end of the lever I2 is connected by pin 52 to a clevis 53 to which the plunger II of the magnet I9 is adjustably connected. A spring 54% seated in a recess in the bearing support plate 49, tends to raise the plunger II and the free end of the lever I2, thereby tending to apply the anti-friction sealing ring 42 to the shoulder 55 of the shaft 29. This spring may be adjusted. It may be substituted by a suitably disposed weight. The shoulder 55 is formed on a shouldered sleeve 56 which has an inwardly extending flange 51 clamped between a shoulder 58 on the shaft section 29 and the lower end 59 of the socketed shaft section 63. The shaft section 90 is journalled at its lower end in the roller bearings 62 as shown in Figure 3, and at its upper end in suitable ball bearings 63 (see Figure 2). The journal shaft section 60 is drilled at its lower end to receive the reduced extension 64 of the impeller shaft section 2 3. Since the pump here shown is adapted for acid service, all of the parts which contact with the liquid to be handled are made of corrosion resisting metal. The fitting 56 and the impeller shaft section 29 are made of corrosion resisting material. So also are the fitting or sleeve 56, the mounting ring 44, and the clamping ring 43 on the diaphragm 34. Similarly, the drip cup 36 is preferably made of corrosion resisting metal for the same reason. The shaft section 69 which does not come into contact with the liquid to be handled, may be made of any structural material, such as plain carbon steel. The reduced extension 64 of the impeller shaft 29 is secured in the socket in the lower end of the journalled section 60 by a forced fit 'whichis designed to make a tight joint betweenthe shoulder 58 and the flange 51. This formed fit is backed up by a cross pin 65 driven into a cross bore in the telescoping member. The'upperend of the sleeve -56-has a counterbore in which is disposed a-filler sleeve 6I. This defines an annular recess for receiving a packing ring 66, which has a suitable follower and spring 6601. to force the same against the lower surface 610i the flange of the bearing supportingring 48. This packing ring 66 may be made of a suitable fibrous material impregnated with an acid resistant grease or oil, and its function is to exclude the escape of lubricant which is supplied to the bearing 62. The bearing 62 comprises the inner race 68 mounted upon shaft section 60 and held thereby a nut '59, and the outer bearing ring 69 mounted in the bearing support ring 49, which isclamped into a recess formed in the frame plate 49. The frame plate 49 is in turn clamped as by means of the bolts I2 to an inwardly extending flange I3 onthe bracket frame 3. The motor support frame 4 has an inwardly extending flange I4 which is clamped by the bolts "I5 to the plate 49,- and it has arched portions extending over the bolts I2 to clear the same.

The motor 5 rests upon the supporting frame 4 and is clamped thereto by means of the flange I1 and cap screws I3 tapped into the motor frame and plate. The motor shaft 19 is keyed as shown at into the coupling member 82 which is connected through a resilient member 83 to a corre* sponding coupling section 84 mounted and keyed on the upper end of the shaft section 60. The bearing barrel 59 provide an annular space through which the upper bearing 63 may be removed by pulling the shaft'section 60 downwardly. Thisannular space is normally filled up by a filler member 85, which reduces the windage and at its lower end serves as a lubricant reservoir. The upper bearing is arranged as indicated for forced lubrication, lubricant being forced in through the nipple 86 and adapted to pass through the bearing and above the flanged end8'I of the filler member and out at the discharge nozzle 83, such discharge indicating that lubricant has passed entirely through the bearing. In a similar manner, the lower bearing is adapted to be lubricated by lubricant introduced at a nipple 89 and passed through an annular space 99 formed between the filler member 85 and the inside of the bearing barrel, and then down through ports 92 through the bearing 62 and out through a suitable passageway 93 formed in the bearing support ring 49 and the passage 94 through the fram plate 49 to a discharge nozzle such as the nozzle 68 shown at the upper bearing.

The impeller shaft section 23 at its lower end has a shoulder 95 formed at the junction of the same with a reduced extension 96. The reduced extension 96 is provided with a Woodruff key 91 which fits a keyway 98 formed in the hub 99 of the lower head I09 of the sealing drum I9. A threaded extension I02 of the shaft section 29 carries a nut I93 for clamping th hub 99 upon the reduced shaft extension 96 and against the shoulder 95. 'Below the threaded extension I92 there is a cylindrical extension I92a, which extends into a cylindrical recess formed in the center of the cover plate I26. This extension I02a has no function in the operation of the pump. It serves during shipment to prevent whipping of the rotor which might spring the same.

threadine't e n I03 u n he ex n I02 and simultaneously drawing up the threaded hub 29 of the diaphragm cup 30 upon the threaded end of the sleeve I! most of the pressure is to be exerted by the nut I03, and the threaded hub 29 is designed merely to take up and on bottoming on the gasket 32 provide the final clearance between the flange I8 and the radial blades I04 on the inside face of the drum head I00.

The drum I9 is formed of two main parts, namely, the head I00 which has the apertured hub 99 previously described, and the upper head portion I which has a cylindrical portion I06 extending down to the outer margin of the lower head I00 to which it is secured by a forced fit on the pilot portion I01 and by the diagonal pins I08 which are et in drilled recesses and then welded over. The diagonal pins lie in planes tangential with respect to the circle of the drum barrel I06. The top drumhead I05 is disposed closely to, the top surface of the sealing disk I8, and at its center opening is spaced a slight distance from the lower end of the sleeve II, so that the space between the disk I8 and the upper head I05 is in communication with the intake zone of the impeller which is carried upon the said head II l5. The impeller I09 comprises a series of blades sweeping a circular channel IIEi having one or more outlet ports II2 leading through ducts II3 to, a main discharge passageway H4, and thence to the discharge connection I5. In the specific embodiment herein illustrated there are three port Il2 disposed equidistantly around the periphery of the channel IIO, and communicating through the volute or circular manifold H4 with the discharge connection I5. The arrangement of impeller blades and discharge ports and volute is similar to that illustrated in my prior Patent No. 2,134,254, of October 25, 1938. I do not intend to confle the form of impeller and ports and volute arrangement to the specific form herein shown, since various forms of blades with various degrees of curvature may be utilized, depending upon the volume and pressure to be developed and the type of service for which the pump elements per se are designed. Also it is not essential that the impeller sweep the channel. A conventional form of volute with a single cutoff cooperating with an open or a closed curved blade impeller may be used. The impeller and easing may be varied without afiecting the novelty of the unit. It is to be understood, however, that the blades are preferably carried by the sealing drum, and that the impeller zone surrounds the sleeves I1, and that an intake zone which consists in the preferred form of the intake chamber 25 and the central recess in the impeller will be utilized, and that there is a passageway extending partly or all the way around the impeller zone an communicating through one or more ports with the impeller zone to receive the fluid discharged from the impeller zone and to deliver it to the discharge connection.

The structure of the pump body herein disclosedlis novel. The intake chamber 25 is defined by the head 24 which has the extending flange II5 to. receive the corresponding flange II'0 of the bracket frame 3, these two flanges being clamped, together by bolts 1. A cylindrical wall I I8, which i opened at the right of Figure 3 to the intake connection I4, defines the periphery of the intake chamber 25. This wall H8 joins the truncate conical wall I I9 to provide the opening I between the inlet chamber and, the impeller chamber.

A cylindrical wall I22 extends downwardly in the case directly from the outer margin of the conical wall H9 to define the periphery of the channel H0 in the sides of which the ports I I2 are located. The wall I22 has a horizontally extending flange I23 at its lower end faced off at I24 for receiving a clamping gasket engaged by the clamping flange I25 of the closure head or disk I26 which closes the bottom of the pump body. The head I25 has an internal bottom surface with a clearance of the order of relative to the sealing drum I9, and since in the specific design of the impeller and sealing box in the pump illustrated the blades I09 extend beyond the confines of the sealing box I9, a filler flange I21 of cylindrical form fills the annular space between the periphery of the sealing drum I9 and the interior cylindrical Wall I22.

Now it is possible to employ the same pump body casting for a line of pumps of different speeds and deliveries by proper proportioning of the impeller blades and sealing box with suitable modification of the closure head which closes the bore of the cylindrical extension I22. A disc I8 of about '7 will seal against 15 p. s. i. at 1750 R. P. M. A disc of about 4 /2 will seal against the same pressure at 3450 R. P. M.

The pump body, with its closure head I25, is supported on the base plate I. The base plate I has a circular upper rim I29 with an inwardly extending flange E39 through which bolts I3I make connection to the clamping ring I32. The clamping ring E32 may be made in sections. It has an inwardly extending flange which overhangs the fiange I23 of the bottom of the pump body, so that the base plate I and the pump body may .be securely clamped together with the head or closure member I25 securely held in place between them and sealed against flange I23 by the gasket I25.

The operation of the pump will now be described.

When the pump is at rest, and has its intake Id connected to a source (not shown) of liquid under pressure, and the discharge connection I5 connected to a discharge conduit (not shown) which retains liquid to an equal or greater head, the pump stands with the parts in the position indicated in the drawings. The main switch I is open. The magnet I5 is de-energized. The spring 54 thrusts the magnet core II upwardly and applies the sealing ring 42 carried on the diaphragm 34 to the shoulder 55 on the shaft. Internal hydraulic pressure from the intake is effective through the impeller of the pump, and through the kinetic seal which now is not operating, and through the inside of the sleeve to put pressure upon the bottom of the flexible diaphragm 3d and force the ring 42 against the shoulder 55 to hold it tight. Thus the intake pressure on the pump tends to hold the static seal tight by the very considerable total force which the liquid exerts upon the diaphragm 3 3. This diaphragm has a rather extensive area, and hence a very substantial unit pressure may be placed upon these static sealing surfaces. It is to be understood that the space between the shaft and the sleeve is full of liquid and that the liquid presses against the bottom of the diaphragm.

When it is desired to start the pump into operation, the motor switch 1 is closed, and this energizes the motor 5 and at the same time energizes the magnet I0. The magnet I0 is of limited power which is not great enough to -9 thrust the mounting ring and diaphragm down against the internal pressure ot the moment of starting. It would not be desirable to let the magnet do this at once because the kinetic seal could not become effective instantly. In accordance with my invention the magnet does not compel the separation of the static sealing surfaces until such time as the kinetic seal has driven liquid by means of the blades I04 around the edge of the disk I8 to the extent of reducing the pressure upon the diaphragm 34 below the power of the magnet, and then the magnet can push the wearing surfaces apart, for from that speed on, the kinetic seal takes charge and allows no liquid to rise into the space [between the sleeve and the shaft. It is to be observed that the blades I04 are disposed solely on the bottom side of the disk I8, and that the head I05 over the disk I8 is a plain surface. While there is some pressure developed by rotation of the head I05 over the disk I3, nevertheless the effect of the blades I04 below the disk is so much greater that the tendency is to drive liquid around the margin of the disk I8 to the point that the seal is almost empty of liquid. The blades I04 are designed to oppose the pressure in the intake zone from the source which supplies the liquid to the pump. Preferably, the blades I04 will pull liquid out of the sleeve and partially empty themselves to the point where a minimum of liquid enters the tips of the blades. Air will not enter because of the positive pressure of the intake supply. The pump is not designed to operate under conditions other than a positive supply of liquid on the intake which will at least in some degree counterbalance the pumping effect of the blades I04. Thus when the pump is running to pump liquid, liquid flows in through the intake connection I4 into the intake chamber 25 and into the central part of the impeller I09 where it is operated upon by the blades running in the channel H0, and discharged out through the ports II2 into the passageways H3 and delivered to the common manifold volute to the discharge connection I5, and thence to the "point of delivery.

If now the pump is to be shut down, the motor switch I is opened, the magnet l is de-energized and thespring 54 tends to thrust the plunger II upwardly and raise the lever to apply the sealing ring 42 to the sealing shoulder 55 on the shaft.

The spring 54 will, upon deenergizaticn of the magnet I0, be free to lift the lever I2 and the mounting ring 40 upon which the anti-friction face 42 is carried and to place the same in relatively light engagement with the shoulder 55 on the rotating shaft. This makes a more or less preliminary seal which constitutes the diaphragm 34 capable of acting as a motor element or piston and which is energized, as soon as the hydraulic seal loses its effectiveness and pressure from the intake begins to be exerted around the disc. I8 into the hollow annular space surrounding the shaft 20. The unit pressure exerted on the contacting surfaces of the static seal may be relatively high, and hence a good seal maintained without any appreciable wear, since the only time that these parts are actually in rub- .bing contact is the time it takes for the spinning rotor to come to rest on stopping, and for the motor to bring the kinetic seal to effectiveness on starting. Thus very little wear is occasioned.

Upon starting the motor, the ring 42 and the shoulder 55 are still held .in tight engagementby '10 e the internal hydraulic pressure under the diaphragm 34, although this pressure is eased to the extent that the magnet I0 presses down on the free end of the lever I2. The magnet I9 will normally be designed to be of relatively low power as compared to the power of the hydraulic diaphragm, with the result that the kinetic seal must begin to be effective before the diaphragm After the kinetic seal has pulled the liquiddownsufliciently to avoid any squirting out of liquid at thegap between these surfaces when they separate, the magnet thrusts the diaphragm down and holds it down so long as the energizjing current is supplied to the motor leads, which are connected in parallel to the magnet I0.

For servicing the pump, the sleeve I! and sealing drum I9 of the kinetic seal, with the impeller blades I09 thereupon, are intended to be removed as a unit. In pumps of this general type, particularly those employed for acid service, the impeller, because of its peculiar duty, is subject to the greatest degree of wear, and is usually the first of the pump parts to require renewal. The intake pipe having been disconnected from the intake I4, the sleeve, drum and impeller unit are now to be removed. To perform this operation, the bolts I3I are released, so that the clamping ring I32 no longer restrains the flange I23 and the pump may be lifted off the base. The lower head I26 is separated from the main pump body, exposing the nut I03 on the lower end of the impeller shaft section 20. The pins 45 that connect the lever I2 to the arms 44 of the mounting ring may, but need not be removed, and the diaphragm 34 is unclamped by loosening the bolts 38. Then by means of a spanner wrench applied to the projection 33 on the flange of the diaphragm cup 30, the diaphragm cup 30 may be turned on its threads on the sleeve I1, and at the same time the nut I03 having been released, the diaphragm cup 30 bearing against the downturned flange of the clamping plate 43, thrusts the bearing ring 42 against the shoulder 55, and thereby forces down the sleeve I? to start the hub 99 of the lower drum head I00 down oif of the reduced extension 96 of the impeller shaft. The key 21 becomes exposed and may be removed, and later the key 9! at the lower end When also becomes exposed and is laid aside. the impeller, sealing drum and sleeve unit have been removed, a completely new unit maybe inserted. The key 21 is first put in place, and this may be viewed through the intake I4. Then the key 91 enters the keyway 98. The hub .29 of the diaphragm cup 30 takes up the slack produced by tightening of the nut I03 which carries the parts upwardly by pressure of; the lower drum head I 00 upon the disk !8 of the sleeve I1. The final takeup of the hub 29 against the gasket 32 lifts the disk I0 ofi of the blades I04 sufliciently to provide the clearance substantially as shown. The outer margin of the dia phragm 34 may then be clamped by replacing the bolts 30. The pins 45 may be reinserted, the whole pump moved back onto the head I26 and clamped in place upon the base by means of the bolts I3I and clamping ring I32.

The present pumpv provides a novel method of activating and deactivating the two seals which are,

is highly advantageous. Assume the parts are at rest. The unit pressure on the contacting surfaces of ring 42 and shoulder 55 which provide the static seal when the pump shaft 20 is not rotating is determined by the intake pressure head. The pressure head acting on the effective area of the diaphragm 34 applies a total force upon these sealing surfaces directly proportional to the head of the liquid to be sealed.

Then, as soon as the switch I is closed and the motor and solenoid H] are energized, the motor starts to accelerate the rotor, and shortly the drum [9 will be operating fast enough to oppose the intake pressure head by the pressure created by the blades I04 on the bottom side of the sealing disk l8. These blades, being full of liquid, will create sufficient pressure to drive liquid around the margin of the disk I8 against the intake pressure head. prevailing in the intake zone.

But meanwhile, the magnet it is exerting a downward thrust against the force of spring 5 and against the much greater force of the hy draulic motor element which the diaphragm 3% represents. Now as the blades Hi4 become effective as above described, they decrease the pressure acting on diaphragm 34 by tending to draw liquid from the sleeve ll until, by the time the motor is at full speed, the pressure on the bottom of the diaphragm has receded to a point less than the downward eifective thrust of the magnet IO and the contactv surfaces of ring 42 and shoulder 55 are out of engagement. The blades I04, in pulling liquid down through the sleeve,

would tend to produce a negative pressure on thebottom of diaphragm 34 if the. separation of the seal parts did not prevent this.

Thus it can be seen that the liquid pumping effectiveness of the kinetic seal determines the opening of the contact parts of the static seal. In other words, it is the coming into action of the kinetic seal that releases the mechanical or static seal.

Similarly, upon opening of the switch I, the motor 5 and magnet It are both deenergized. The motor takes a few moments to slow down to a stop, but the magnet relaxes its pull at once. No dashpot or delay mechanism is necessary. The spring 54 takes over from the magnet and applies the ring 42 lightly against the shoulder 55 until the blades [t4 have begun to lose effectiveness and allow the intake pressure to push liquid past them and create pressure in the cup 39 against the diaphragm. When the shaft 25 stops, the full pressure of the intake head is applied to the diaphragm and the contacting surr faces of the static seal are held firmly together.

Thus it can be seen that upon stopping the pump, the positive or static seal is closed before the kinetic seal loses its effectiveness.

I do not intend to be limited to the details shown and described, as obvious variants will occur to those skilled in the art within the spirit and scope of the appended claims.

I claim:

1. For use in a pump of the class described, a sealing sleeve adapted to be disposed vertically and having a threaded upper end, a diaphragm cup threaded upon the end of the sleeve, a centrally apertured flexible diaphragm, a clamping 12 thereof, a mounting ring fixed to the margins of the diaphragm about the central aperture thereof, arms on the mounting ring having pin sockets above the cylindrical flange and an antifriction sealing ring secured upon the mounting ring.

2. The combination of claim 1 with a vertical pump shaft extending down through the diaphragm aperture and having a radially extending shoulder facing, and adapted to be engaged by, said anti-friction ring, and a lever for shifting said mounting ring and its anti-friction ring toward or away from said shoulder, said lever having branches adjacent said arms, and pins pivoting said arms and lever branches together.

3. In a pump of the class described, a vertical sleeve having a horizontally disposed sealing disk at its lower end, a diaphragm cup at its upper end, a centrally apertured flexible diaphragm clamped at its outer margin to the cup, a sealing ring attached to the diaphragm about the aperture, a shaft extending down through the aperture and the sleeve and having a sealing shoulder adapted to be engaged by the sealing ring to make a contact seal, a hydraulic sealing drum embracing the sealing disk, the lower head of the drum being mounted on. the lower end of the shaft, the upper head of the drum being apertured and embracing the sleeve, impeller blades carried by said upper head, and a pump casing having an impeller chamber embracing said blades, and an inlet chamber surrounding the sleeve and communicating through an annular opening with the impeller chamber, said inlet chamber having a central opening into which the upper end of the sleeve is fastened.

4. In a pump of the class described, a main pump body comprising walls defining an intake chamber having a lateral inlet opening, said walls including a head having a central opening or bore with a keyway in the lower part of the bore in line with said inlet opening, said body comprising walls defining an impeller and seal chamber below the intake chamber and in communication therewith, a combined impeller,

sealing drum and sleeve unit comprising a sleeve carrying a disk at its lower end and having its upper end threaded and having a shoulder intermediate its ends with a key above said shoulder to cooperate with said keyway, said unit comprising also a sealing drum embracing the disk, said drum having an opening in its upper head embracing the sleeve, impeller blades carried on the drum, said drum having a bore through its lower head with a keyway in said bore, a driving shaft extending down through the sleeve and having a threaded lower end and a shoulder adjacent thereto, and carrying a key above said shoulder to cooperate. with the keyway in said bore, a nut for clamping the said lower head and shaft together, and a key on the shaft engaging the keyway in the bore. of said drum head before the key on the sleeve engages the keyway in the bore in the. intake chamber head.

5. In a pump, av hollow body having walls defining an intake zone, an impeller zone below and around the same, and a discharge zone surrounding the impeller zone, said zones all communicating, an annular impeller operable in the impeller zone to create a pressure difference between the intake and discharge zones, intake and discharge connections communicating with the intake zone and, discharge zone respectively, a central sealin sleeve extending vertically through said zones and being sealed at its upper end to the walls of the intake zone, a shaft extending loosely through said sleeve and carrying said impeller at its lower end, bearings for the shaft external of the sleeve, said sleeve and said impeller having cooperating portions defining a, kinetic liquid seal between the intake zone and the inside of the sleeve disposed below the impeller, and a static contact seal between the sleeve and the shaft disposed above the impeller.

-6. In combination in a pump of the class described, a pump casing having an inlet chamber wall, a tubular sleeve adapted to be disposed vertically, said sleeve having a liquid sealing disc at its lower end and having its upper end extending through and sealed to the inlet wall of the pump casin a diaphragm cup attached to the upper end of the sleeve, a diaphragm on said cup, said diaphragm having a central aperture with a wear ring about the aperture, a shaft extending loosely down through the diaphragm aperture and the sleeve and having a, shoulder cooperating with said wear ring, a liquid sealing drum on the lower end of the shaft, said drum embracing the stationary liquid seal disc and carrying an impeller upon the upper head of the drum, the drum having a lower head upon the inside of Which there are liquid pumping blades for producing a pressure at the bottom side of the margin of the disc superior to the intake pressure on the pump, whereby the said blades tend to withdraw liquid from the inside of the sleeve and reduce the pressure of the liquid upon the diaphragm while the pump is in operation, sprin means for pulling on the disc to cause it to press the wear ring against the shoulder of the shaft whereby when the pump is not in operation, the internal pressure in the pump causes the diaphragm to press the seal ring against the shoulder, and an electromagnet having a movable member connected to said diaphragm, said electromagnet being adapted to be engaged contemporaneously with energization of the driving motor, said magnetic member when the electromagnet is energized opposing the action of the spring.

7. For use in a pump of the class described having a drive shaft adapted to be disposed in a vertical position and carrying a, liquid impeller at its lower end, a tubular sleeve adapted to be positioned coaxially with the pump drive shaft and surrounding the same, said sleeve having an integral disolike flange at its lower end adapted to cooperate with the pump impeller to form a kinetic sealing disc, said sleeve being threaded at its upper end, a diaphragm cup threaded to the upper end of said sleeve, said cup having a pcripheral clamping flange, a flexible diaphragm apertured at its center and clamped at its outer margin to the flange of said diaphragm cup, and a sealing ring fixed to the margin of said diaphragm about the central aperture, said sealing ring having a pair of operating arms for applying mechanical force to said ring.

8. For use in a pump of the class described, a tubular sleeve adapted to be disposed in a vertical position and having an integral disolike flange at its lower end forming a kinetic sealing disc, a diaphragm cup threaded upon its upper end, said cup having a peripheral clamping flange, a flexible diaphragm apertured at its center and clamped at its outer margin to the flange of said diaphragm cup, a sealing ring fixed to the margin of said diaphragm about the central aperture, said ring having a pair of operating arms for applying mechanical force to said ring, and a clamping ring coaxial with the cup for securing said diaphragm on the flange of said cup, said clamping ring having a cylindrical flange extending above the sealing ring and a radial flange extending inwardy and overlyin the diaphragm to limit its upward deflection.

9. For use in a pump of the class described, a tubular sleeve, a centrally apertured kinetic sealing disc joined centrally to the lower end of the sleeve, a centrally apertured diaphragm cup secured centrally upon the upper end of the sleeve, a centrally apertured flexible diaphragm disc secured peripherally to the outer margin of the diaphragm cup, a sealing ring secured to the central margin of the outside of the diaphragm disc about the aperture, a clamping ring for securing said diaphragm to the margin of the cup, said clamping ring having a cylindrical flange extending upwardly above and coaxial with the sealing ring and having a flange extending radially inward and. overlying the diaphragm to limit its upward deflection, and a clamping ring inside the cup cooperating with the sealing ring and having downwardly projecting portions adapted to engage the bottom of the cup for limiting the downward deflection of the diaphragm.

10. For use in a pump of the class described, a tubular sleeve adapted to be disposed in a vertical position and. havin an integral disolike flange at its lower end forming a kinetic sealing disc, a diaphragm cup threaded upon the upper end of said sleeve, said cup having a peripheral clamping flange, a flexible diaphragm apertured at its center and clamped at its outer margin to the flange of said diaphragm cup, a sealing ring fixed to the margin of the diaphragm about the central aperture, said sealing ring having a pair of operating arms for applying mechanical force to said ring, a clamping ring for securing the diaphragm on the flange of the cup, said clamping ring having a cylindrical flange concentric with and extending above the sealing ring and a radial flange extending inwardly and overlying the diaphragm to limit its upward deflection, and. a grooved mountin ring clamped to the margins of the diaphragm about its central aperture, said sealing ring comprising a ring of anti-friction material carried in the groove of said mounting ring.

HARRY E. LA BOUR.

REFERENCES CITED The following references are of record in the file or this patent:

UNITED STATES PATENTS Number Name Date 1,346,924 Wilfley July 20, 1920 1,421,389 Bischof July 4, 1922 1,869,824 Richter Aug. 2, 1932 1,947,017 McHugh Feb. 13, 1934 2,240,607 Buck May 6, 1941 2,258,527 Warman Oct. '7, 1941 2,381,823 La Bour Aug. 7, 1945 2,381,824 La Bour Aug. 7, 1945 

